For the latest issue of New Humanist, I interviewed Robert Lambert, the former Metropolitan Police detective who ran the Muslim Contact Unit, a Special Branch team which, from 2002-2007, was responsible for working with Muslim groups within London to combat the influence of al-Qaeda sympathisers.

The MCU, and Lambert in particular, became controversial due to their choice of partners – in order to counter the activities of extremists such as the infamous Abu Hamza, the MCU worked closely with Muslim groups which are themselves viewed by many as hardline. In Finsbury Park in north London, where Abu Hamza and his followers had seized control of the local mosque, the unit developed a close partnership with two Islamist groups, the Muslim Association of Britain and the Muslim Welfare House, while south of the river in Brixton they worked with a group of black converts who follow a literalist Salafi interpretation of Islam.

Since leaving the police, Lambert has continued to attract controversy. He is now researches Islamophobia as an academic and runs the European Muslim Research Centre at Exeter University, which has received heavy criticism on account of being funded by the Cordoba Foundation, which has a close relationship with the Islamist Muslim Brotherhood (David Cameron has described it as a "front" for the Brotherhood). He has remained close to various Islamists, and has recently been criticised for supporting Raed Salah, the Palestinian preacher who is fighting deportation from the UK amid accusations of inciting anti-Semitic hatred.

The MCU's strategy and Lambert's relationship with Islamists are discussed in more detail in my piece, but the reason I'm also publishing this blog post is that the story took an unexpected twist after our magazine went to press. On 16 October, it was revealed in the Guardian that Lambert had worked as an undercover police spy in the environmental and animal rights movements during the 1980s. Under the name "Bob Robinson", he posed as an activist in London Greenpeace between 1984 and 1988, and even had an 18-month relationship with a fellow activist who was unaware of his true identity until the revelations broke last month.

Inevitably, the revelations about his undercover work in the environmental movement raised questions about his work with Muslim groups after 2001, not least for the groups that actually worked in partnership with him. In a statement, he has reassured his Muslim partners of his "ability to build genuine trust with groups campaigning for social justice" and pointed to his book on his MCU work, Countering al-Qaeda in London, as evidence of his "good faith moving forward".

While the revelations don't intrude directly on the subject of my interview with Lambert, clearly it will have to be read with this news in mind. For those who have criticised him for becoming too close to hardline Muslims, his activities in the environmental movement in the 1980s could be viewed as further evidence of an alleged tendency to "go native" in his police work. Meanwhile, for those sympathetic to his arguments around Islam and terrorism, his emphasis on partnership could be undermined by his history of spying on activist groups.

As you'll see if you read my piece, I end by considering where Lambert's arguments fit in to the wider debate over counter-terrorism and counter-extremism. Should the authorities simply be looking to prevent violence, or should they take a broader approach and reject all hardline Islamic groups, with a view to moulding a moderate, distinctly British version of Islam? The revelations about Lambert clearly have no bearing on these questions, but, depending on how you view them, they could be seen to undermine his own contributions to the debate.

For the latest issue of New Humanist, I interviewed Robert Lambert, the former Metropolitan Police detective who ran the Muslim Contact Unit, a Special Branch team which, from 2002-2007, was responsible for working with Muslim groups within London to combat the influence of al-Qaeda sympathisers.

The MCU, and Lambert in particular, became controversial due to their choice of partners – in order to counter the activities of extremists such as the infamous Abu Hamza, the MCU worked closely with Muslim groups which are themselves viewed by many as hardline. In Finsbury Park in north London, where Abu Hamza and his followers had seized control of the local mosque, the unit developed a close partnership with two Islamist groups, the Muslim Association of Britain and the Muslim Welfare House, while south of the river in Brixton they worked with a group of black converts who follow a literalist Salafi interpretation of Islam.

Since leaving the police, Lambert has continued to attract controversy. He is now researches Islamophobia as an academic and runs the European Muslim Research Centre at Exeter University, which has received heavy criticism on account of being funded by the Cordoba Foundation, which has a close relationship with the Islamist Muslim Brotherhood (David Cameron has described it as a "front" for the Brotherhood). He has remained close to various Islamists, and has recently been criticised for supporting Raed Salah, the Palestinian preacher who is fighting deportation from the UK amid accusations of inciting anti-Semitic hatred.

The MCU's strategy and Lambert's relationship with Islamists are discussed in more detail in my piece, but the reason I'm also publishing this blog post is that the story took an unexpected twist after our magazine went to press. On 16 October, it was revealed in the Guardian that Lambert had worked as an undercover police spy in the environmental and animal rights movements during the 1980s. Under the name "Bob Robinson", he posed as an activist in London Greenpeace between 1984 and 1988, and even had an 18-month relationship with a fellow activist who was unaware of his true identity until the revelations broke last month.

Inevitably, the revelations about his undercover work in the environmental movement raised questions about his work with Muslim groups after 2001, not least for the groups that actually worked in partnership with him. In a statement, he has reassured his Muslim partners of his "ability to build genuine trust with groups campaigning for social justice" and pointed to his book on his MCU work, Countering al-Qaeda in London, as evidence of his "good faith moving forward".

While the revelations don't intrude directly on the subject of my interview with Lambert, clearly it will have to be read with this news in mind. For those who have criticised him for becoming too close to hardline Muslims, his activities in the environmental movement in the 1980s could be viewed as further evidence of an alleged tendency to "go native" in his police work. Meanwhile, for those sympathetic to his arguments around Islam and terrorism, his emphasis on partnership could be undermined by his history of spying on activist groups.

As you'll see if you read my piece, I end by considering where Lambert's arguments fit in to the wider debate over counter-terrorism and counter-extremism. Should the authorities simply be looking to prevent violence, or should they take a broader approach and reject all hardline Islamic groups, with a view to moulding a moderate, distinctly British version of Islam? The revelations about Lambert clearly have no bearing on these questions, but, depending on how you view them, they could be seen to undermine his own contributions to the debate.